Thank you for posting your question here at brainly. Below is the solution:
F = ma
In this case m = m car + m truck; a is assumed constant and not need for the answer.
F = F accelerate the car + F accelerate the truck.
a is the same for both, so the F accelerating the car is ½ half the force accelerating the truck.
F truck = 2 x F car
F = F car + 2 F car = 4500 --> F car = 1500; F truck = 3000
The car is pushing against the truck with 3000 N force.